CBQE-385 comment-out warmup hang test case of 5000000 docs

Change-Id: I878cb1aed2db7a0cdbdc3ad13ed09695c82fc7c3
Reviewed-on: http://review.couchbase.org/24228
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>